The invention addresses problems which have been encountered especially with in-ear hearing aids.
In-ear hearing aids are typically produced by first making an impression of the ear canal and then molding the custom-moulded ear-plug shell from the impression. Yet in the ear canal, in-ear hearing aids are exposed to substantial dynamic movement of the area of application, i.e. the auditory canal, for instance during mastication, so that, notwithstanding a precisely adapted fit of the hearing aid based on the impression with subsequent fine adjustment, in practice the device is not fully satisfactory in terms of wearing comfort. This is due in part to the fact that the usually rigid custom-moulded ear-plug shells cannot absorb the aforementioned dynamic movement. On the other hand, in the basic design of the hearing-aid shell especially in the case of in-ear hearing aids, consideration must always be given to the need for miniaturization, the accommodation of complex electronic modules and the assurance of reproducible, stable acoustic conditions.
However, the problem of dynamic movement of the area of application, encountered with in-ear hearing aids, also presents itself with other custom-moulded ear-plug devices, albeit often to a lesser extent, devices which in practice are worn on other parts of the body and which in daily life are subjected to a certain dynamic movement. In other words, while the problem is particularly pronounced in the case of in-ear hearing aids and, obviously, of in-ear custom-moulded ear-plug devices in general, for instance parts of earphones, noise- or water-blocking ear plugs, it also exists for pinnal hearing aids and custom-moulded ear-plug devices.
It is the objective of this invention to introduce custom-moulded ear-plug devices which solve the above-mentioned problems, in due consideration of the severely restricted physical space available for in-ear custom-moulded ear-plugs and especially in view of the stringent requirements for in-ear hearing aids in terms of their acoustic properties. This is accomplished in that, at least in one section of its outer surface and/or, in the case of an custom-moulded ear-plug shell, of its inner surface, the custom-moulded ear-plug device features a pattern of longitudinally elongated profiles, or, if the custom-moulded ear-plug device is provided with a shell constituting its outer surface, in that at least one section of the inner surface of said shell features a pattern of longitudinally elongated profiles.
The structural pattern thus produced determines in regionally specific fashion the flexibility and/or compressibility of the custom-moulded ear-plug unit. For example, following the proposed approach it is possible to configure the elongated profiles in the form of structurally stabilizing fins or ribs on what is otherwise a relatively thin custom-moulded ear-plug shell. The layout, contouring and density of the ribs are by themselves entirely capable of ensuring the flexibility of the custom-moulded ear-plug device that is necessary for absorbing the dynamic movement inherent in the application.
In a preferred embodiment of the custom-moulded ear-plug device according to this invention, a combination of the above-mentioned features is employed, i.e. the shell of the custom-moulded ear-plug unit is provided with both inner and outer profiles. Where for an custom-moulded ear-plug device compressibility and/or flexibility is required in a relatively well-defined section, it is suggested that the profiles in that area extend along continuous closed paths around the custom-moulded ear-plug unit, preferably in an undulating or bellows-like pattern. Looking for instance at an in-ear custom-moulded ear-plug device with a profile orientation between an area facing the tympanic membrane and an area facing the pinna, i.e. the opening of the auditory canal, and if the longitudinal direction of the custom-moulded ear-plug device is defined as extending between these two areas, it becomes evident that the mentioned configuration of the profiles, following continuous, closed or helical paths in planes essentially perpendicular to the said longitudinal direction, leads to a substantially enhanced flexibility or compressibility of the custom-moulded ear-plug unit. This is especially true if the profiles on the inner and outer surfaces are mutually offset in the aforementioned longitudinal direction and the profiles are formed by protuberances of the shell wall proper.
In another preferred design implementation, also easily combinable with the aforementioned embodiment, the profiles form a grid pattern in at least one section of the custom-moulded ear-plug unit, providing a local mechanical reinforcement of the custom-moulded ear-plug unit in that section and, if the latter is in the form of a shell; allowing the areas between the profiles to be extremely thin-walled. A grid or lattice pattern of this nature produces a high level of dynamic absorptivity while in the case of custom-moulded ear-plug units with a shell also permitting the use of an extremely thin-walled shell, reinforced only by the said profiles. The orientation and the cross-sectional dimension of the profiles provided are determined by varying profile shapes, which offers another measure of design flexibility in defining the mechanical properties of the custom-moulded ear-plug device according to this invention. Yet another design parameter that can be added consists in a shape variation of the profiles over their longitudinally extended paths.
In summary, the proposed design features will yield custom-moulded ear-plug devices individually customizable in specific regions in adaptation to the particular requirements relative to their structural properties, meaning flexibility and compressibility. The concept per this invention is implementable with virtually no added bulk, since the proposed profiles permit a reduction of the wall thickness of the custom-moulded ear-plug shells. At the same time, the acoustic requirements can be fully satisfied, given that by means of the features per this invention such as localized reinforcements. the mechanical properties of the custom-moulded ear-plug shell or fully enclosed custom-moulded ear-plug device can be optimized.
If the custom-moulded ear-plug device is designed as an in-ear custom-moulded ear-plug unit with a region facing the eardrum and another region facing the outer ear, it is recommended that the profiles on the outer surface of the custom-moulded ear-plug unit be provided with at least one groove freely extending between the mentioned regions and defining a venting groove.
The last-mentioned measures per this invention also make it possible to easily provide for air to reach the tympanic membrane.
Another preferred design version of the custom-moulded ear-plug device per this invention features a shell with the above-mentioned profiles as well as a filler material contained in and essentially filling the shell and adapted to the intended function of the custom-moulded ear-plug unit.
If the custom-moulded ear-plug device according to this invention is to incorporate certain modules such as electronic components, batteries, converters etc., as is the case especially with hearing aids, it is recommended that, in the design version last mentioned, a cavity or receptacle be provided within the filler material for accommodating such module or modules in the custom-moulded ear-plug unit.
Another embodiment of the custom-moulded ear-plug device per this invention is already equipped with the above-mentioned modules and is preferably designed as a hearing aid and most preferably as an in-ear hearing aid.
The following describes implementation examples of this invention, and other custom-moulded ear-plug design versions combinable therewith, with the aid of the attached drawings in which: